A prolific of illuminated keyboards have been developed and disclosed in prior art for desktop and notebook computers to facilitate keyboard operation in a low brightness or dark environment. References can be found in U.S. Pat. Nos. 6,284,988, 6,322,229, 6,199,996, 6,554,442 and 6,179,432, and R.O.C. patent Nos. 509955, 465777, 535385, 438035, 570235, 468833 and 516671. They all have a build-in lighting sheet to emit light to enable users to clearly judge striking positions of a keyboard. They also have a common feature, namely the light color of the illuminated keyboard is fixed and unalterable. As a result, the light color and brightness of the illuminated keyboard cannot be adjusted as desired. The light color or brightness could be too strong and irritate users' eyes, or too dark or weak and cause input errors.
To remedy the aforesaid problem, techniques to adjust light color of illuminated keyboards have been developed. There are mainly two methods to adjust the light color. One is adjusting the light color through computer software, such as R.O.C. patent publication No. 200636672. It discloses a keyboard and a method to select the color of keys on the keyboard. The keyboard has a backlight module including LEDs of red, green and blue colors. Through a color tuning software, various colors can be displayed on a computer screen to allow users to select required colors. By selecting the color emitted by the LEDs, color adjustment can be accomplished. China patent publication No. CN1763879 discloses a keyboard backlight module and method thereof. It also has a keyboard backlight module consisting of LEDs in red, green and blue colors. Through a color tuning software, the ratio of various colors can be displayed on a computer screen, then users can adjust the color ratio to mix and generate a desired color. The adjustment methods mentioned above have to rely on the color tuning software.
There is another method which adjusts the light color of an illuminated keyboard through keys on the keyboard, such as R.O.C. patent No. M310388. It discloses a keyboard with adjustable lighting brightness. The keyboard has a plurality of light color switches each corresponding to a different light color. By depressing the light color switches, the light color of the illuminated keyboard can be changed. But its light color switches are set to corresponding fixed light colors. Selection is confined to the fixed light colors, and users cannot adjust light color and brightness according to their requirements.